When Leonardo Nakao’s flight from Brazil landed in Bos­ton at 1:30 a.m., he didn’t have to search long for a job. By 5 a.m., he was pumping gas at a suburban service station. It was July 4, 2000, and Brazilian immigrants were enjoying a star-spangled boom.

More offers poured in. In his first week in the United States, Mr. Nakao got seven calls about jobs to fill the two days he wasn’t working. He was soon earning $1,000 a week. Then, two years ago, the global recession hit. Work got more strenuous, and the value of the dollar had fallen relative to Brazil’s real, slashing the value of the $400 a month he sent to his family in Brazil.

“It’s difficult, with the dollar low. The employment is not easy. The rent is high. The gasoline is high,” Nakao said on a rare break from his 80-hour/$1,200-a-week landscaping job. “If the opportunities were better and the immigration laws more favorable, I’d think about staying.”

Instead, he was counting the days – just eight more at the time of this interview – until he followed the 20 members of his family who had already left the US in the last two years to go back home.

It’s a calculation that many of America’s newest residents are making. For some, the US remains the best place to make a living, despite its economic woes and tougher stance on immigration. For others, the lure of home has grown, especially when home has escaped the depths of the global recession. No one knows how many Indians, Chinese, or Brazilians have left in the past two years. The US gave up trying to track emigration in the late 1950s. But estimates and anecdotal evidence suggest that for Brazilians, at least, more are leaving than ever before.

The outflow is leaving its mark on places like downtown Framingham, Mass. The Boston suburb, founded in the 1600s by English settlers, began to acquire its Latin flair in the late 1990s when placards in Portuguese and the green, yellow, and blue of the Brazilian flag began popping up in once-vacant downtown storefronts. By mid-2005, one-quarter of Framingham’s residents was foreign-born, the vast majority of them Brazilian. An estimated 70 percent of the stores downtown are Brazilian-owned.

In the past two years, however, the number of Brazilians living here has dwindled. Local estimates vary widely – up to 40 percent have left, according to the owner of one prominent local flower shop.

“There’s [fewer] immigrants out on the streets,” says Gilberto Yoshida, president of Chang Express, which has been selling plane tickets to South America for 16 years. His company saw a “tremendous spike” in one-way tickets to Brazil sold last winter, which is when seasonal construction and outdoor work tend to dry up. What is clear is that almost no new immigrants are coming in.

“Zero. Zero. Zero. No one is coming from Brazil,” says Manuel Barilio, as he counts the handwritten entries in his spiral notebook where immigrants register to say they’re looking for work. Mr. Barilio, director of the Bom Samaritano social services center in Framingham, says he now gets at most a handful of entries each day.

The change is evident statewide. Massachusetts, once a top destination for Brazilian immigrants, along with Florida, New Jersey, and New York, used to receive about 50,000 a year during the boom years, says Fausto da Rocha, executive director of the Brazilian Immigrant Center in Allston, Mass. In the past two years, about 17,000 of the state’s approximately 200,000 Brazilians have gone back home, he estimates.

He expects up to 7,000 to decamp this year – and more in 2010 unless the US passes immigration reform that allows illegal immigrants to work in the US.

“The economy and immigration crackdown – that’s what pushed the Brazilians back,” Mr. da Rocha says. During the first half of the decade, Brazilians were the second-fastest-growing group of illegal immigrants to the US (behind Indians), according to Alan Marcus, a professor of geography at Towson University in Maryland.

This isn’t the first time reverse migration has picked up during a time of economic change. In the 1990s, Irish immigrants returned home to participate in that country’s economic boom. A surge of Mexican immigrants left the US in the 1930s, and the number of Italians leaving then was far greater than those coming in, says Donna Gabbacia, who teaches immigration history at the University of Minnesota in Minneapolis. After peaking at 14 million in 1930, the number of foreign-born in the US dropped every decade through 1970 – initially because of the economy but also because of stringent immigration quotas, according to the Migration Policy Institute (MPI), a nonpartisan research organization in Washington.

“I think it’s perfectly possible [the foreign-born population] could shrink” again, Professor Gabbacia says, depending on the economy and changes to US immigration and refugee policies. It’s wrong to think “that once you get here, you stay here.”

The drop in immigrants has hurt some of Framingham’s businesses. In the first half of the decade, South Exchange in downtown Framingham handled an average of 10 money transfers a day. That’s dropped to fewer than four now. So in May, manager Renato Alves diversified into selling airline tickets.

“Tickets are more business to deal with because people are leaving,” he says. He says he’s already gotten some 200 calls about flights and sells three one-way tickets for every round trip one sold.

Down the street, an employee of Made in Brazil Express also says most of her company’s ticket sales have been one-way trips to Brazil.

“If [Brazilians] leave, if they’re passing through a difficult time, we also are going to be,” says Nubia Gaseta, president of a local business association. Her own company, which provides flowers for events and gifts, saw sales fall 30 percent two years ago and another 50 percent in the past year.

Brazilians don’t necessarily represent the vanguard of a larger migrant outflow. Other Latinos have not begun pulling up stakes by and large, points out Aaron Terrazas, an MPI policy analyst. One reason: Most of their home countries can’t match Brazil’s robust growth, which is drawing migrants back. (A typical estimate is that an immigrant can earn in one week in the US what he could earn in four in Brazil, says Maxine Margolis, a retired anthropologist at the University of Florida in Gainesville. It would take some 10 weeks in Mexico.)

Comparisons with reverse migration during the De­pres­sion are overblown, says Mr. Terrazas. The key now is mobility. “We’re in this age where there’s so much movement,” he says. “It’s easier and cheaper.”

Nakao is proof of that. He didn’t know what he would do when he got back to Brazil. He might join his brothers, who had already returned and work as mechanics in Brasília. He might farm in the north.

Will he come to the US again? “I want to go back to stay,” he says. “But I don’t know how things will be.”